Fig. 2.

Energy landscape of Piezo vesicle shape. Stationary lipid membrane bending energy $G_M\left(R_P;R_v\right)$ as a function of Piezo dome radius of curvature $R_P$ for (A) the Piezo vesicle radius $R_v\approx 24.7 \text{nm}$ [vesicle 3 in figure 4 of our companion paper (10)] and (B) the Piezo vesicle radius $R_v\approx 35.0 \text{nm}$ [vesicle 6 in figure 4 of our companion paper (10)] together with selected vesicle cross-sections. These correspond to $R_P=R_1=7.6 \text{nm}$, $R_P=R_{\text{min}}^M\approx 9.67 \text{nm}$ in A and $R_P=R_{\text{min}}^M\approx 10.1 \text{nm}$ in B, $R_P=R_2\approx 16.7 \text{nm}$, and $R_P=R_3\approx 27.4 \text{nm}$. In A, $R_2$ is equal to the observed value of $R_P$, $R_2=R_{\text{obs}}$, while $R_3=R_{\text{obs}}$ in B. For each Piezo vesicle, we describe the Piezo dome geometry as a spherical cap with fixed cap area $A_{\text{cap}}$. The in-plane Piezo dome radius $r_b$ and the Piezo dome contact angle $\alpha$ associated with the predicted free membrane shapes in figure 4 of our companion paper (10) determine, for each Piezo vesicle, $A_{\text{cap}}$ via $A_{\text{cap}}=\frac{2\pi r_b^2}{1+\cos \alpha }$. (Scale bars, 5 nm.) (C) The table shows $R_{\text{obs}}$ vs. $R_v$ for the seven Piezo vesicles in figure 4 of our companion paper (10). The corresponding spherical cap areas $A_{\text{cap}}$ are approximately $471$, $414$, $421$, $471$, $428$, $444$, and $442 {\text{nm}}^2$ (from top to bottom).